Because an ocular optical system is very complicated and it is very difficult to handle as it is, various simulated eyes have been considered as a standard optical model of an eyeball. In addition, studies of the optical characteristics of an eyeball (e.g., changes of various optical images when an intraocular lens is implanted) have been conducted by using such simulated eyes or by computer simulation using optical constants calculated from such simulated eyes.
Various lenses such as a progressive multi-focus lens are presently being developed in the field of eyeglass lenses. However, it has heretofore not been possible to objectively observe how things are seen when a subject wears an eyeglass lens. This difficulty has been a big obstacle in the research and development of eyeglass lenses.
Although it is conceivable to use an optical system corresponding to an eyeball to actually simulate an image (retinal image) of an object when seen through an eyeglass lens, the following problems have presented themselves when a ready made industrial lens, a photographing lens or the like are used in such a simulation.
When an optical system replacing an eyeball as shown in FIG. 14 is used, while light which is transmitted through an eyeglass lens advances toward a pupil of an eye (pupil entrance), brightness of an image and the size of a field of view change when a distance between the apexes of the rear faces of the eyeglass lens, the retina and the position of the pupil (position of the pupil entrance) shift. Therefore, it is necessary to give due consideration to the above-mentioned distance and the position so that they can be set correctly. However, the eyeglass lens and the state of the eyeball cannot be simulated by ready-made photographic and industrial lenses because the position of their object side principal point and that of the pupil entrance are located on the rear side as compared to the eyeball, and the distance between the apexes cannot be set correctly. That is, because the brightness of the image and the size of the field of view largely change in simulating the retinal image by using an eyeglass lens and an optical system such as ready-made photographing lenses, the eyeglass lens cannot be evaluated correctly.
Accordingly, it is an object of the present invention to provide an artificial vision lens system as well as an artificial vision camera and an artificial vision system suitable for simulating a retinal image of naked eyes or an image created when a subject wears eyeglass lenses.